Whole Sunflower Seed as a Fat Supplement for Lactating Cows

Complete rations containing whole sunflower seed at 0, 10, 20, and 30% of concentrates were fed to 16 Holstein cows during early lactation. All rations consisted of corn silage, alfalfa hay, and grain mixtures and were formulated to be isonitrogenous at 16% protein and nearly isocaloric at 1.50 Mcal net energy lactation per kilogram of dry matter. Intakes of total dry matter were not different among ration groups. Cows fed 10% sunflower seed produced more milk and were more efficient energetically. Treatment did not affect milk composition. Average secretion of shorter chain fatty acids in milk from caproate to palmitate was depressed, whereas oleate was increased by sunflower seed. Molar percentage of acetate was increased, and remaining variables measured in rumen fluid were not altered by dietary treatment. No health or feeding problems associated with whole sunflower seed supplement were observed during the entire trial. Graded increase of sunflower seed in the diet elevated cholesterol in blood serum with no effect on cholesterol in milk. Blood urea nitrogen remained unchanged, and total serum protein decreased with increasing sunflower seed in the diet.